Free SaaS SEO ROI Calculator (MRR, CAC, Payback)

I keep seeing the same thing happen.

A SaaS team wants to “do SEO this year” (or redo it, again), someone asks what it’ll cost, and the answer turns into a foggy mix of vibes, screenshots of Ahrefs, and a random “we should see results in 3 to 6 months”.

Then the hard questions show up.

How much MRR could this realistically generate?
What CAC does SEO even have for us?
How long until we get our money back?
And… are we about to spend 6 months publishing content that never ranks.

So here’s what I’m giving you in this post: a free SaaS SEO ROI calculator you can copy into Google Sheets, plus the exact formulas, plus a few examples so you can sanity check your numbers.

And yes, we’ll cover MRR, CAC, and payback period. The stuff your CFO cares about. The stuff that makes SEO either a no brainer or a quiet budget cut.

Also, if you’re trying to do this with less human time, I’ll mention a hands off option near the end. (Because agencies are expensive, and in house content ops is… a whole lifestyle.)

What you’re calculating (in plain English)

When someone says “SEO ROI”, they usually mean:

1. How much revenue can organic traffic produce
2. How much it costs to get that revenue
3. How long it takes to earn back the cost

For SaaS, you want the unit economics version:

• New MRR from SEO
• SEO CAC (cost to acquire a customer through SEO)
• Payback period (months)
• And optionally: LTV and LTV:CAC, because that’s the language SaaS runs on

A tiny but important note: SEO revenue is rarely instant. There’s lag. So your calculator should handle time, not just totals.

The “Free ROI Calculator” you can paste into a sheet

Create a Google Sheet with these columns. I’ll keep it simple first, then we’ll add the nicer stuff.

Inputs (top section)

Put these in cells (or wherever you like). Example layout:

Traffic + conversion

• Monthly organic sessions (target): T
• Visitor to signup conversion rate: CVR1
• Signup to paid conversion rate: CVR2
• Or combined visitor to paid rate: CVR = CVR1 * CVR2

Revenue

• Average MRR per customer: MRR_avg
  (Use average. If you have multiple plans, weighted average is best.)
• Gross margin (optional): GM
  (If you want ROI on gross profit, not revenue.)

Costs

• Monthly SEO cost: Cost_m
  (Agency retainer, salaries, tools, content, links, whatever you’re counting.)
• One time SEO cost (optional): Cost_1x
  (Migration, technical cleanup, big content sprint.)

Retention

• Monthly churn rate: Churn_m (optional)
• Or average customer lifetime in months: Life_m (optional)

Core formulas (MRR, customers, CAC)

1) New customers from SEO per month

If you have combined visitor to paid conversion:

New_Customers = T * CVR

If you split conversions:

New_Customers = T * CVR1 * CVR2

2) New MRR from SEO per month

New_MRR = New_Customers * MRR_avg

3) SEO CAC

This is the one people mess up. CAC is cost per customer acquired.

If you’re measuring monthly steady state:

SEO_CAC = Cost_m / New_Customers

If you have one time cost too, amortize it (simple approach):

Effective_Cost_m = Cost_m + (Cost_1x / Amort_Months)

Then:

SEO_CAC = Effective_Cost_m / New_Customers

Amort months can be 6, 12, 18. Pick something consistent with your SEO ramp expectations.

4) Payback period (months)

Payback is how long to recover CAC from gross profit (or revenue, if you insist).

If using gross margin:

Payback_m = SEO_CAC / (MRR_avg * GM)

If using revenue:

Payback_m = SEO_CAC / MRR_avg

Gross margin is the more honest version for SaaS, but either is fine as long as you don’t pretend they’re the same.

Add LTV (so the ROI conversation becomes easier)

If you know churn, you can estimate lifetime and LTV quickly.

Option A: churn based LTV (simple)

If monthly churn is Churn_m, average lifetime in months is roughly:

Life_m = 1 / Churn_m

Then LTV (revenue version):

LTV = MRR_avg * Life_m

Or gross profit LTV:

LTV_GP = (MRR_avg * GM) * Life_m

Option B: known lifetime

If you already have a known average lifetime:

LTV = MRR_avg * Life_m
LTV_GP = (MRR_avg * GM) * Life_m

LTV:CAC

LTV_to_CAC = LTV_GP / SEO_CAC

Most SaaS teams like 3:1 as a rough baseline, but SEO often looks better than paid because it scales weirdly. Just don’t ignore the time lag.

The missing piece: SEO ramp and “time to break even”

The reason SEO ROI spreadsheets lie is because they assume month 1 looks like month 12.

In reality, SEO ramps. Content gets indexed, climbs, earns links, builds topical authority, all that slow boring magic.

So you want a monthly model.

Build a 12 month table

Create columns:

• Month (1 to 12)
• SEO cost (monthly)
• Organic sessions (estimated)
• Customers
• New MRR
• Cumulative cost
• Cumulative MRR
• Net (cumulative MRR minus cost)

Step 1: estimate a traffic ramp

You can do it a few ways:

Simple linear ramp:
Traffic in month m = T_target * (m / 12)

More realistic ramp (slow early, faster later):
Month multipliers like:

• Month 1: 5%
• Month 2: 8%
• Month 3: 12%
• Month 4: 18%
• Month 5: 25%
• Month 6: 35%
• Month 7: 45%
• Month 8: 60%
• Month 9: 75%
• Month 10: 85%
• Month 11: 95%
• Month 12: 100%

Then: T_m = T_target * Multiplier_m

Step 2: customers and MRR each month

Customers_m = T_m * CVR
New_MRR_m = Customers_m * MRR_avg

Step 3: cumulative totals

Cum_Cost_m = Cost_1x + (Cost_m * m)
Cum_MRR_m = SUM(New_MRR_1 : New_MRR_m)
Net_m = Cum_MRR_m - Cum_Cost_m

Your break even month is the first month where Net_m turns positive.

That’s the payback story most founders actually want.

A worked example (so you can check your sheet isn’t broken)

Let’s use normal-ish SaaS numbers. Not perfect, just believable.

Assumptions

• Target organic sessions: 50,000/month (at month 12)
• Visitor to paid CVR: 0.35% (0.0035)
• Average MRR: $120
• Gross margin: 85% (0.85)
• Monthly SEO cost: $4,000
• One time cost: $3,000 (setup, fixing pages, whatever)
• Ramp: the multiplier table above

Month 12 steady state snapshot

Customers:

• 50,000 * 0.0035 = 175 customers/month

New MRR:

• 175 * $120 = $21,000 new MRR/month

SEO CAC (steady state):

• $4,000 / 175 = $22.86 CAC

Payback (gross profit):

• CAC / (MRR * GM) = 22.86 / (120 * 0.85)
• 22.86 / 102 = 0.22 months

That looks insanely good. Which should immediately trigger a second thought.

Because in real life:

• conversion rates vary by keyword intent
• not all traffic is product relevant
• you won’t hit 50k in 12 months unless your site and strategy are solid
• and you still have onboarding, sales assist, churn, expansion, etc

So this example isn’t “SEO is free money”. It’s showing why the ramp model matters. Early months will be negative.

If your ramp means month 1 is 5% of target traffic:

• 2,500 sessions
• 2,500 * 0.0035 = 8.75 customers
• New MRR = 8.75 * $120 = $1,050
• Cost is still $4,000 (plus the one time) So yeah. Ugly early. Better later.

That’s SEO.

A more conservative way to model conversion (recommended)

If you want numbers you can defend in a meeting, don’t use one CVR for all SEO traffic.

Split keywords into buckets:

• High intent: “best [category] software”, “[competitor] alternatives”, “pricing”, “vs”
• Mid intent: “how to”, “templates”, “examples”
• Low intent: definitions, glossary, general info

Then assign different conversion rates. Even rough ones are better than pretending every visitor behaves the same.

In the sheet:

Customers_m = (T_hi * CVR_hi) + (T_mid * CVR_mid) + (T_lo * CVR_lo)

It takes 5 extra minutes and makes your ROI model way less naive.

What counts as “SEO cost” (so CAC isn’t fantasy)

You can make SEO CAC look amazing by excluding half the costs. People do it all the time.

A reasonable monthly SEO cost includes:

• Content production (writing, editing, visuals)
• SEO tools (crawler, keyword research, content optimization)
• Technical SEO work (dev time or contractor)
• Internal time (your team’s hours, at least roughly)
• Links and digital PR (if you do it)
• Content uploads and formatting (this is weirdly expensive in time)

If you want the CAC number to be trusted, count the real costs.

If you’re trying to reduce cost and time, this is where automation platforms can be a legit alternative to hiring an agency.

(That’s basically the pitch of SEO Software, it scans your site, builds a keyword strategy, generates SEO articles, and schedules and publishes them for you. The point is fixed monthly cost, less operational mess.)

The fastest way to improve your ROI assumptions (without guessing)

A few quick checks I like:

1) Use real conversion data from organic already

Even if your organic traffic is small, pull:

• organic sessions
• organic signups
• organic paid conversions

Then compute your current visitor to paid CVR and use that as a base case.

2) Use Search Console to estimate reachable traffic

Pick a set of pages or topics you can realistically publish in the next 90 days. Estimate traffic from impressions and average position movement.

3) Validate content quality before scaling

If your content doesn’t match intent, conversion will be trash even if you rank.

This is where an on-page workflow helps. Run a quick audit using an on-page SEO checker or an editor that forces basic completeness. Even better if it’s connected to publishing so things actually ship.

Mini calculator: “Should we hire an agency or use software?”

Not everyone wants this in the ROI calculator, but it comes up immediately, so here’s a simple comparison framework.

Option A: SEO agency

• Typical cost: $3k to $15k/month
• Pros: strategy and human guidance
• Cons: output varies wildly, depends on team, lots of coordination, you still do approvals, publishing, internal linking, etc

Option B: in-house content team

• Cost: higher than you think (salary, management, tools)
• Pros: brand context
• Cons: slow ramp, hiring and training, ops overhead

Additionally, it's crucial to understand when to leverage different marketing strategies. For instance, SEO vs PPC for SaaS can provide insights into which approach might yield better results based on your specific circumstances.

Option C: automation platform

Fixed monthly cost, automated production and publishing, decent if you already know you need consistent content output.

If you’re curious what this looks like in practice, SEO Software for SaaS is positioned exactly for that. AI driven strategy, bulk article generation, content calendar, internal linking, multilingual, publishing to CMSs.

And if you’re comparing it to the usual suspects, these pages are handy:

• SEO Software vs Surfer SEO (more workflow automation vs content scoring)
• SEO Software vs Jasper (more SEO and publishing system vs general AI writing)

Not saying “never hire humans”. Just saying there’s a middle option now that didn’t exist a few years ago.

A simple template you can copy (with headings you can paste into Sheets)

Here’s a clean structure. Copy these as row labels.

Inputs

• Target monthly organic sessions (month 12)
• High intent % of traffic
• Mid intent % of traffic
• Low intent % of traffic
• CVR high intent (visitor to paid)
• CVR mid intent
• CVR low intent
• Avg MRR per customer
• Gross margin
• Monthly SEO cost
• One time SEO cost
• Ramp model (list of month multipliers)

Monthly model (table)

• Month
• Sessions
• Customers
• New MRR
• SEO cost
• Cumulative cost
• Cumulative MRR
• Net

Summary outputs

• Customers/month at steady state
• New MRR/month at steady state
• SEO CAC at steady state
• Payback months (gross profit)
• Break even month (from cumulative net)

Common mistakes (quick, but important)

Using traffic as the goal instead of revenue

A page that gets 20,000 visits and converts at 0.02% is not a win. It’s a distraction. Your calculator should punish low intent traffic.

Forgetting the ramp

If you pitch month 1 ROI like month 12, you’re going to lose trust fast.

Mixing “new MRR” and “total MRR”

Be consistent. If you’re counting new MRR each month, your cumulative is the sum of new MRR. If you want active MRR, you need churn modeling. Most teams don’t need that complexity to make a decision.

Not fixing the pages you already have

Sometimes the best ROI is updating and improving existing pages. Not pumping out 60 new ones.

If you want a quick starting point for that, run an audit and start cleaning obvious issues. Even a basic guide like improve on-page SEO can help you spot the low hanging stuff.

And if you’re editing content actively, using an AI SEO editor can speed up rewrites without losing structure.

Wrap up (and a practical next step)

If you only do one thing after reading this, do this:

Make the sheet. Put in your real MRR, your real conversion rate, and your real monthly SEO cost. Then add the ramp.

You’ll instantly see:

• what “good SEO” would need to produce to be worth it
• how sensitive ROI is to conversion rate
• and the month you actually break even

And if you want the easiest operational path to actually hit those publishing numbers without building a whole content machine, take a look at SEO Software. It’s built for hands-off SEO content production, strategy, scheduling, publishing, and rewrites. Basically the parts that usually eat your week.

That’s it. Copy the calculator, adjust the assumptions until they stop lying, and you’ll have an SEO ROI story you can defend.